diff --git a/ngc_hs1.cpp b/ngc_hs1.cpp
index b6852ab..d62d343 100644
--- a/ngc_hs1.cpp
+++ b/ngc_hs1.cpp
@@ -581,7 +581,7 @@ void _handle_HS1_ft_recv_data(
 				group_number, peer.id.value(),
 				static_cast<Tox_Message_Type>(transfer.recv_buffer.front()),
 				transfer.recv_buffer.data()+1,
-				data_size-1,
+				transfer.recv_buffer.size()-2,
 				transfer.msg_id
 			);
 		}
@@ -618,14 +618,15 @@ void _handle_HS1_ft_send_data(
 	// get msg
 	const auto& message = group.peers.at(msg_peer).dict.at(msg_id);
 
-	size_t i = 0;
+	size_t data_i = 0;
 	if (data_offset == 0) {
 		// serl type
-		data[i++] = message.type;
+		data[data_i++] = message.type;
+		data_offset += 1;
 	}
 
-	for (; i < data_size; i++) {
-		data[i] = message.text.at((data_offset+i)-1);
+	for (size_t i = 0; data_i < data_size; i++, data_i++) {
+		data[data_i] = message.text.at(data_offset+i-1);
 	}
 
 	if (data_offset + data_size == 1 + message.text.size()) {